1. Field of the Invention
The present invention relates to horizontal window blinds and, more particularly, concerns horizontal window blind designs having modular components which can be used to manufacture window blinds of varying sizes in an efficient manner.
2. Description of the Related Art
Horizontal window blinds are commonly used window coverings. Typically, the horizonal window blinds consist of a head rail member, that contains both a tilting mechanism and a lifting mechanism, and a plurality of horizontal slats that are connected to the head rail and are arranged in parallel so as to be able to be positioned in front of the window when the head rail member is mounted to the window frame. The slats are generally mounted on string ladders which are attached to the tilting and lifting mechanisms contained within the head rail. The string ladders are essentially comprised of two vertical string members having a connecting piece extending therebetween. The slats are generally positioned on or captured by the string ladders so that the outer edges of the slats are positioned inside of the vertical strings with the slats resting on or between the horizontal connecting pieces of the string ladders.
The lifting mechanism is generally comprised of at least two lifting strings that are adapted to be threaded through openings formed at the outer ends of each of the slats and are then anchored in a bottom rail. The lifting strings are attached to a pulley and catch mechanism or a roller and lock mechanism such that the operator, by pulling on a drawstring, can either raise or lower the slats. The tilting mechanism is generally comprised of a relatively small dimensioned rotatable member that is positioned within the head rail so as to extend across the width of the window. Typically, a rod is attached to a gear mechanism such that user rotation of the tilt rod induces the rotatable member to rotate within the head rail. The outer support strings of the ladders are attached to the rotatable member such that rotation of the rotatable member results in vertical displacement of one outer support string relative to the other thereby causing the slats interposed therebetween to rotate or tilt.
Hence, a user can vary the amount of light entering a room by manipulating the tilting mechanism so as to adjust the slats in the rotational or tilted position. The position of the slats typically can continuously vary between a first position, where the plane of the slats is essentially perpendicular to the plane of the window thereby allowing light to enter through the blinds, and a second position, where the plane of the slats is essentially parallel to the plane of the window thereby preventing light from entering through the blinds.
While horizontal window blinds of the type described above are commonly used, there are several difficulties associated with these window blinds. Initially, many of the components used in prior art window blinds are expensive to manufacture and are relatively easily damaged. For example, the head rail is typically made out of relatively thin metal, such as aluminum or steel, that can be easily damaged during assembly, shipping, or installation. Damaged head rails will often interfere with the correct operation of the tilting mechanism or the lifting mechanism thereby preventing the blind from operating correctly.
In particular, the headrail itself must be cut to the desired length. The cutting process, however, often results in the walls of the headrail becoming bent. As components have to be positioned within the headrail, bent or deformed headrail walls often can prevent correct installation of the components within the headrail. Moreover, to even form the headrails, expensive equipment must often be used. For example, the headrail must not only be cut to size but also pressed into the desired shape. Hence, a window blind manufacturer must purchase both presses and shears to form the headrail member and the act of forming the headrail often results in damage to the headrail that complicates the assembly of the window blind.
Moreover, the assembly of most commonly available prior art window blinds is very time consuming and labor intensive which results in relatively high assembly costs. For example, in many prior art window blinds, intricate gear mechanisms typically interconnect the user actuating tilt rod to the rotatable member positioned within the head rail. This intricate gear mechanism can require a considerable amount of effort to install this intricate mechanism within the head rail. In general, the components that are to be mounted within the headrail generally have to be positioned within a confined opening defined by the headrail itself. As the headrails are only several inches in cross-section and depth, there is not a lot of room for an assembler to handle and interconnect the components within the headrail. Hence, the assembly and positioning of the components in the headrail can be a very time consuming task for the assembler due to the limited amount of space within the headrail.
A further difficulty that adds to the expense of manufacturing prior art window blinds is that different sizes of blinds often require different size components. This often requires the manufacturer to stockpile large, unwieldy, difficult to store raw components. For example, large pieces of the materials used to form the headrails must be stored so that these pieces can be subsequently cut and shaped to form headrails adapted to fit different sizes of windows. As the material is thin and the raw pieces are typical quite long, the material often gets damaged in storage which results in both significant wastage of material and time consuming efforts to reshape the material for subsequent use.
A further difficulty stems from the fact that window blinds are preassembled in a factory in standard or custom sizes and then shipped to the job site in an assembled format. However, the headrails can also be easily damaged during shipment due to the thinness of the materials used to form the headrail. Once the headrail is damaged, it may no longer be possible to mount the headrail in a window frame or the damage to the headrail may impair the correct operation of the lifting and tilting mechanisms contained within the headrail. As a consequence, damaged headrails are typically returned to the manufacture r for repair adding to the manufacturers costs. An additional difficulty relating to shipping is that the assembled headrails of the prior art are typically made out of metal materials and are quite heavy. As such, the overall shipping costs of the window blinds of the prior art can be quite expensive.
Yet another difficulty of window blinds of the prior art is that the headrails must be almost exactly the right size to be correctly mounted within the window. Typically, the headrail is mounted at either end to the window frame. If the headrail is too long, it will not fit within the window. Further, if the headrail is too short, the mounting brackets that are mounted to the sides of the window frame will generally not engage the headrail and will not securely hold the window blind to the window frame. A significant source of damage to prior art window blinds occurs when installers attempt to fit a mis-measured headrail into a window frame.
Moreover, often times the standard sized prior art window blinds are not well adapted for use with larger windows. In these circumstances, the installer must use multiple blinds to cover a single large window. This results in a window blind assembly that can have an undesirable appearance. This problem is further exacerbated by the typical construction of the window blinds which makes it difficult to produce window blinds having a width of greater than generally four feet. Hence, for larger windows, multiple blinds must be installed. However, multiple blinds often have an undesirable appearance and also require the manipulation of multiple sets of controls to adjust the blinds.
Yet another problem with window blinds of the prior art is that the headrail is often covered by a decorative valence. The decorative valence can be made of a nicer appearing material that the plain metal of the typical headrail. However, the attachment of the valence to the headrail is often unsatisfactory. Either a simple hook and loop fastener is used to secure the valence to the headrail or a more complicated catch mechanism is used. The problem with the simple hook and loop fastener is that, over time, the fastener becomes ineffective resulting in the valence not being securely fastened to the headrail. Moreover, the more complicated catch mechanisms add to the expense of the window blind and often have an undesirable appearance.
Hence, from the foregoing, it will be appreciated that there is a need for a window blind assembly which is simplified in design, less prone to damage, easier to install and is more readily adaptable to cover windows of different sizes. To this end, there is a need for a window blind assembly which has modular components that can be flexibly mounted together to result in the assembly of window blinds of a variety of sizes in a simple and inexpensive manner.